In reinforced concrete construction applications, such as highways, floors, or walls of buildings, spacer devices, commonly referred to as chairs, are required for supporting and maintaining reinforcing rods or bars which are positioned in the area where concrete is to be poured. These reinforcing rods are sometimes referred to as “rebars”. Depending on such parameters, such as the total surface area and the thickness of the end product of concrete, reinforcement is mandated in varying degrees by building codes. One such method of reinforcement involves a steel mesh, while in major concrete construction, such as highways and high-rise buildings, reinforcing rods of various diameters, typically one-half inch or more, are required. In addition, on such jobs, the reinforcing bars may be positioned in spaced layers due to the thickness of the floor. In some installations, a first layer of rebar is provided, with the reinforcing rods or rebars in spaced parallel relationship, and generally parallel to the surface on which the concrete is to be poured. A second layer of rebar is then added, with the orientation of the second layer perpendicular to the first layer, thus forming a grid or lattice work. After the reinforcing bars or lattice work is prepared, the concrete is then poured over this grid or framework, which is ultimately embedded within the highway floor or wall.
For a concrete floor on a prepared surface, spacers or chairs are utilized for providing the vertical separation of the rebar grid from the surface on which the concrete is to be poured. The prepared surface may be a wood, plywood, or foam structure or a compacted surface, the latter of which my be provided with a layer of compacted sand, with a plastic sheet covering thereon providing a moisture barrier. Spacers or chairs are then positioned on the prepared surface for supporting the rebars in a plane generally parallel to the prepared surface. Typically, with modern building codes, a spacer is needed for every linear foot of the rebar.
With rebar spacers or chairs, one common problem is occasioned by the number of different sizes required to be maintained by a supplier to accommodate different thicknesses of poured concrete, such as two-inch, three-inch, four-inch, etc. and many intermediate fractional sizes. Another common problem with rebar spacers has been encountered in the method of securing the rebar to the chair or spacer, with twisted wire being the most common method. This particular problem is more acute when mutually perpendicular layers of rebar are coupled to the same chairs or spacers. With wire connections, a first strip of wire secures the first layer and a second strip of wire secures the perpendicular layer of rebar. With any metal or wire within the reinforcing bar grid work, there is a problem with rusting or decomposing of the wire or metal components.
In the past, various patents have issued relating to these chair supports for reinforcing rods. In particular, the present inventor is the owner of U.S. Pat. Nos. 5,555,693 and 5,791,095 for such chairs. Each of these chairs has a receiving area with a horizontal section and a generally parabolic section extending transverse to the horizontal section. A plurality of separate legs extends downwardly from the receiving area. Each of the legs has a foot extending horizontally outwardly therefrom. The receiving area and the plurality of legs are integrally formed together of a polymeric material.
U.S. Pat. No. 3,788,025, issued on Jan. 29, 1974 to S. D. Holmes, describes a chair for supporting in right angular relation two reinforcing rods used in construction. The chair has a lower arched base part and an upper rod supporting part integral with the base. The base is an arched support with means for providing lateral, longitudinal, vertical support and strength. The rod supporting part comprises two spaced apart arms, the lower parts of which form a saddle for receiving one reinforcing rod and the upper part for each of which is formed by two separate spaced upstanding inwardly concave arms, the upper ends of which are spaced to provide an opening through which a second reinforcing rod, arranged at a right angle to the first rod, may be introduced.
U.S. Pat. No. 3,673,753, issued on Jul. 4, 1972 to G. C. Anderson, teaches a concrete reinforcing bar support in which a base supports an upright pedestal. A lower clamping portion is supported by the pedestal which has a first rod-receiving open passageway therethrough. Resilient detents extend from the lower clamping portion to retain a reinforcing rod disposed through the first passageway. An upper clamping portion is provided which includes a pair of hook members extending from the lower clamping portion. Each of the hook members has a mouth opening in the same direction to define a second rod-receiving passageway which is normally disposed to the first passageway.
U.S. Pat. No. 4,835,933 issued on Jun. 6, 1989 to F. P Yung, describes a spacer assembly which includes a spacer with a body having a base portion with a generally centrally disposed support post portion. One end of the support post portion is formed as a planar surface with a centrally located generally concave saddle portion configured for receiving a reinforcing bar. The planar surface is provided with apertures therethrough on both sides of the saddle. A clamp member is provided for simultaneously securing mutually perpendicular rebars to the chair. The clamp member is a generally U-shaped lower portion, with the depending arms thereof in spaced generally parallel relationship for engaging a first bar within the saddle. A generally identical pair of hook arms extends upwardly from the bight portion. The hook arms are oriented for engaging a second rebar in an orientation perpendicular to the first rebar engaged within the saddle portion.
U.S. Pat. No. 5,893,892, issued on Apr. 13, 1999 to Hardy, Jr. et al, teaches an apparatus for fixating and elevating an interconnected rebar lattice having individual longitudinal and transverse rebar intersections. The apparatus includes a holding portion having an open-ended recess with two opposing walls being generally U-shaped. The recess has longitudinal access and is sized and shaped to receive a longitudinal rod. An arc-shaped portion extends laterally outwardly from each opposing wall and perpendicular to the longitudinal access of the recess. The arc-shaped portion includes a recess and an opposing wall with each wall including a snap-type lock. A locking member has a generally arc-type portion and includes a snap-type lock for attaching to the arc-type portion and engaging with the snap-type lock of the arc-type portion. A leg portion extends downwardly from the holding portion and is integrally attached to a base.
Recently, various tests have been carried out with regard to bar supports. A common type of test employed determine the integrity of the chair for the support of rebars and/or wire mesh. This test is known as a “dragging” test. Often, specifications for construction jobs require the particular chairs to withstand the dragging of the wire mesh and/or rebar for a desired distance. As a result, it is a requirement that such intersectional chairs remain secured in their proper positions even though the rebars are being dragged to a particular position.
In the past, various bar supports have been made entirely of plastic materials, such as relatively inexpensive polystyrene, polypropylene or polyethylene. Generally, in the past, the use of nylon has been avoided because of the water retention characteristics of nylon. As such, the benefits of nylon have not been used in conventional chairs in the past.
It is an object of the present invention to provide a bar support which is corrosion-proof.
It is another object of the present invention to provide a bar support that is adaptable to receive various diameters of rebar therein.
It is another object of the present invention to provide a bar support adapted for use at intersections of rebars.
It is another object of the present invention to provide a bar support that can be placed on various flat surfaces.
It is another object of the present invention to provide a bar support that can be easily snap-fitted onto and locked around a reinforcing bar.
It is another object of the present invention to provide a bar support which allows a free flow of concrete therethrough.
It is a further object of the present invention to provide a bar support with a load-resistant stable support structure.
It is another object of the present invention to provide a reinforcing bar support that can retain the rebar even during dragging of the associated wire mesh and/or rebar.
It is still a further object of the present invention to provide a reinforcing bar support that achieves the advantages associated with the use of nylon material.
It is a further object of the present invention to provide a reinforcing bar support which is easy to use, easy to manufacture and relatively inexpensive.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.